The present invention relates to polyol emulsions of castor oil and monoepoxides and to polymer cements prepared therefrom together with methylenediphenyl diisocyanate (MDI) and cement.
The preparation of polymer cements from castor oil emulsions, MDI and cement is known and is described in GB 2353993. The castor oil emulsions used there are, however, relatively highly viscous and therefore not optimally processable.
JP 2001-302304 and JP 2004067463 describe polyol emulsions of castor oil and the reaction products of castor oil with monoepoxides. The viscosity of these emulsions is lower than that of pure castor oil emulsions, but the preparation of the ricinoleic acid/monoepoxide adducts requires an additional reaction step.
Furthermore, the ricinoleic acid/monoepoxide adducts still contain OH groups, which are capable of forming hydrogen bridge bonds and thus increase the viscosity.
Emulsions of castor oil and a reactive diluent which contains no OH groups, but, under the basic reaction conditions of the polymer cement formation, forms free OH groups which then react with the MDI with crosslinking are therefore desirable.